<!DOCTYPE html>
<html>

<head>
	<meta charset="UTF-8">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0">
</head>

<body>
	<script>
		//=>监听A发送过来的信息
		window.onmessage = function (ev) {
			// console.log(ev.data);
			//=>ev.source:A
			ev.source.postMessage(ev.data + '@@@', '*');
		}
	</script>
</body>

</html>